Cold nut former

ABSTRACT

A nut forming machine of the conventional cold nut forming type employing a frame body mounting a crank shaft; a power source and belt drive means; a ram carrying first, second, third stage punches and a piercing punch; respective cooperating die sets; punch out means; rocking means; stock feeding and blank cutter means; transfer clamp means; and a cut off base mounting a slide block for actuating the blank cutter wherein (1) the ram is connected at its laterally opposed ends by respective crank arms mounted through spherical bearings on the crankshaft which in turn is mounted by spherical bearings in the side walls of the frame body; (2) the cut off base is integrally cast with the frame body and provided with slide surfaces in the form of replaceable slide plates; (3) the lateral spacing of the die holes and cooperating punches of the several forming stages and the lateral spacing of the blank cutter from the first forming stage are equal enabling the employment of a simple drive link connected to the slide block of the cutter and the clamper of the transfer clamp means to effect timed driving of the latter means; and (4) the die holes, conventionally provided in the frame body end wall, are formed in replaceable bushings mounted in bushing holes in the frame body.

United States Patent 1 l i 11 3,903,556 Lee 1 1 Sept. 9, 1975 1 1 COLD NUT FORMER [76] lnventor: Yuan Ho Lee, No. 82, Jen Ho Rd. [57] ABSTRACT Tainan Taiwan, China /Taiwan A nut forming machine of the conventional cold nut formin t e em 10 in a frame bod mountin a 122] Hlcd: May I974 crank s haf t a po ver so urce and belt d rive means; a [21 Appl. No.: 474,619 ram carrying first. second, third stage punches and a Relaed US. Application Dam piercing punch; respectii/e cooperating die sets; punch out means, rocking means, stock feeding and blank [63] Continuation-inpart of Scr. No. 401,419, Sept. 27, Cutter means; transfer Clamp means; and a Cut f base [973' uhandoncd' mounting a slide block for actuating the blank cutter wherein (l) the ram is connected at its laterally p- [52] [1.5. CI .1 /76 H posed ends by respective Crank arms mounted Lhrough 51 Int. um. 1, B2ld 53/24 Spherical hearings on the Crankshaft which in mm is 1581 held g 10/1 1 l 1 1 1 12 mounted by spherical bearings in the side walls of the 10/1" 72 72 76 76 T frame body; (2) the cutoff base is integrally cast with the frame body and provided with slide surfaces in the 1561 References Cited form of replaceable slide plates; (3) the lateral spacing UNITED STATES PATENTS 0f the die holes and cooperating punches of the sevl 992 3lh 2/I935 Kucbrich .1 10/76 R eral forming stages and the lateral spacing of the blank ZJMJI ll/l 4l Wilcox r i i lU/lO R cutter from the first forming stage are equal enabling 1542A h4 2/1951 Friedman v 4 10/76 T the cn' ployment f a imple j ivg link cgnnech d 16149361 M954 Schueffer et a1. 10/72 R the Slide hlOck of the Cutter and u damper of the (11959 9 10/12 T transfer clamp means to effect timed driving of the lat 219831152 5, 196! Mitchell et a1 1 l 1 .1 10/115 Primary Examine/ Cv W. Lanham Ass/Hun! lixrlminvr-li M4 Combs Armrm'y. Again. m- Fimi-Strauch Nolan, Neale, Nies & Kurw ter means; and (4) the die holes, conventionally pro vided in the frame body end wall are formed in re placeable bushings mounted in bushing holes in the frame body.

4 Claims, 7 Drawing Figures O 56 53 57 54 a 58 l l0 "J11 0 5 2 1 1 Q4114 2 To I 0 v 11 i3, 0 a 41 5 44 o a 81 E162 am Q 82 5 o 1 111 1 7a 40 91 7 7 I2 76 92 FIG.1

PATENTEU 1975 sum 1 or g PATENTED SEP 9 I975 SHEET 2 QF 4 PATENTEDSEP 1915 sum u 95 g COLD NUT FORMER CROSS REFERENCE TO RELATED APPLICATION This is a continuation-in-part of application Ser. No. 401,419, filed Sept. 27, 1973, and entitled NUT FOR- MER now abandoned.

BACKGROUND OF THE INVENTION The present invention relates generally to a nut former, and more particularly to an improved cold nut former of simplified construction which can be manufactured at a reduced cost and maintained in effective operating condition at lower cost.

In the prior art, cold nut formers are generally provided with a single crank connection for driving the ram which supplies the necessary impact force. In nut forming operation, the ram is required to deliver a considerable impact force. In driving the ram with a single crank connection as is done in prior art machines, difficulty is encountered in aligning the centers of the connecting rod and ram. As a consequence, an uneven force is delivered by each individual punch mounted in the front end of the ram and the required accurate positioning of the ram with respect to the slide surface of the ram guide plate will change all the time. As a consequence, the guide plate in its travel over the ram slide surface will produce undesired localized wear of the slide surface.

Also, in the prior art machines the crank shaft is supported by plain bearings adjacent its opposite ends with the result that excessive wear and high starting friction at the beginning of each operation exists resulting in reduced power and low efficiency which necessitates the provision of an air clutch device. Furthermore, the driving of the transferring clamp is effected by means of a cam mounted on the crank shaft and a connecting rod. Any error in the cam, due to designing and manufacturing, will produce a problem in synchronizing the sequence of operations for both cutting the blank and feeding the blank to the transfer clamp.

Also, in order to facilitate the replacement of parts when the cut-off base becomes damaged by wear or the sliding guide gets worn, the cut-off base of the prior art machines are formed as a separate replaceable casting fixed to the frame by means of screw fasteners. This results in the necessity of providing a more sophisticated mechanical construction and additional parts. Moreover, during assembly or replacement, considerable time is required to adjust the replacement base relative to the die base (namely the body frame and wall) and each individual die hole formed in the end wall.

SUMMARY OF THE INVENTION It is a primary object of this invention to provide a cold nut former of high productivity which is simplified and can be manufactured and maintained in efficient operating condition at low cost.

A further object of the present invention is to provide an improved cold nut former including double crank arm connections between the crank shaft and ram to better stabilize the ram as it slides along the guiding surface thereby assuring delivery of a uniform impact force by each punch on the front end of the ram and minimizing wear and deformation of the slide surfaces.

A more particular object of the present invention is to provide a nut former wherein the driving source of the transferring clamp is the cutter slide. the lateral spacing of the blank cutter to the first forming stage and the successive 2nd, 3rd and piercing stages being equal to permit use of a simple drive link in place of a number of connecting mechanisms required in conventional nut formers.

A further object of the present invention is to provide spherical roller bearings for the rotating protions of the crank shaft thereby minimizing frictional resistance during the starting operation, eliminating the clutch and other associated parts required in conventional nut formers.

Still another object of the present invention is to provide a nut former having a cut-off base formed integrally with the frame body and providing replaceable guide plates to serve as inside slide surfaces for the cutoff base to thereby improve the stability of the cut-off base during operation and permit worn slide surfaces to be renewed by guide plate replacement without the necessity of unscrewing and removing the cut-off base and making alignment and other adjustments of the replacing cut-ofi' base and associated machine parts as before.

Another object of the present invention is to provide a nut former wherein the die holes are formed in die hole bushings removably mounted into bushing cavities in the frame body end walls thereby permitting die hole wear to be cured by merely inserting new bushings.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and features of the present invention will become apparent from the following description and appended claims when read in conjunction with the accompanying drawings wherein:

FIG. 1 is a perspective view of the nut former of the present invention;

FIG. 2 is a plan view of the nut former of FIG. I;

FIG. 3A is a top to bottom inverted rear elevational view of the nut former of FIG. 1 omitting for the purpose of clarity the driving source and associated drive pulleys;

FIG. 3B is a front elevational view of the nut former of FIG. 1 omitting for the purpose of clarity the driving source and showing the associated crankshaft pulley in dot dash lines;

FIG. 3C is a partial sectional view taken along the line A-A of FIG. 2 looking toward the left end of FIG.

FIG. 4 is a sectional view taken along line A--A of FIG. 2 looking in the direction of the arrows; and

FIG. 5 is an enlarged fragmental sectional view taken substantially on line 5-5 of FIG. 2 to illustrate a form of die bushing contemplated by this inventor.

DESCRIPTION OF THE PREFERRED EMBODIMENT With continued reference to the drawings wherein the same reference numerals are used throughout to indicate the same parts, the nut former of this invention includes a base frame I0 the sides 11 and 12 of which are provided with opposed coaxial bearing housings II, 12' respectively mounting the self-aligning spherical roller bearings 21, 21 provided by this invention. Bearings 21, 21 journal crank shaft 20 with its opposite ends projecting beyond frame sides 11 and 12. Inwardly of sides II and 12 at the opposite ends 22, 23 of the crank shaft eccentric, shaft 20 is fitted, according to this invention, with respective self-aligning spherical roller bearings 24, 24 which journal the hubs 31, 31 of respective identical crank arms 30, 30 of this invention. The ends 3232 of arms 30, 30 are connected by conventional pin connectors to the opposite ends 41, 42 of ram 40 to assure an even laterally aligned advancement of ram 40.

Crank shaft 20 is driven by an electrical motor 50 by means of motor pulley 51 Vbelt connected to an enlarged shaft pulley 52 on the projecting end 25 of crank shaft 20. Upon rotation, crank shaft 20, through crank arms 30, 30, reciprocates ram 40 which is conventionally slidingly supported at its opposite ends by slide ways 13, 13 of frame and slide surface 14', of respective removable guide plates l4, 15 (See FIG. 3C).

Ram 40 conventionally mounts on its front face respective laterally aligned, equally spaced punches 83, 84, 85 and piercing punch 91 (FIG. 2 and 3C), so that the nut forming operations are performed in response to reciprocating movement of ram 40. As best seen in FIG. 2, the cutter 67 of the present invention is laterally spaced from punch 83 of the first forming stage a distance equal to the distance between punches. The purpose of this particular spacing will be hereinafter pointed out.

As best shown in FIGS. 3A and 4, a cut-off base 16 is formed integrally with frame 10. A link 54 connected at one end to an eccentric wheel 53 fixed to end 26 of crank shaft is connected at its other end to a slide plate 60 (FIGS. 2, 3A and 4), which is guided along laterally spaced ways on the bottom of base 16 by an undercut in body frame side 11 and an opposed removable wedge plate 60' (FIG. 2) to reciprocate slide plate 60 in response to rotation of eccentric wheel 53 and shaft 20. Guide plates 61 rigidly fixed on cut-off base 16 slidingly engage slide block 64 to assure its movement in a direction normal to that of link 54.

A hollow cylindrical slide 62 extending parallel to the guide direction of guide plates 61, mounts roller assembly 65, including a cylindrical follower roller extending into a cam groove 63 (FIG. 2) formed in slide plate 60 positioned beneath the hollow cylindrical slide 62. The opposite ends of groove 63 are laterally offset to assure a reciprocation stroke of slide 62 equal to the spacing between the respective forming stages. The fixed housing of roller assembly 65 is concentrically related to the axis of hollow cylindrical slide 62 and slide block 64 and interconnects slide 62 and slide block 64. Since reciprocating movement is transmitted to slide plate 60 in synchronism with the rotational speed of crank shaft 20, the follower of assembly 65 under the guidance of guiding groove 63 will reciprocate hollow cylindrical slide 62 and slide block 64 from the position shown in FIG. 4 to the right and then back to the FIG. 4 position in synchronism to rotation of shaft 20. This hollow cylindrieal slide 62 fixedly mounts blank cutter 67 (FIG. 2) at its inner end and is provided for the purpose of conventionally performing the blank cutting operation in the nut former. The other end of hollow cylindrical slide 62 mounts a return spring 66. Spring 66 is provided to bias slide 62 to the left as seen in FIG. 4 and assure a full and quick return of cylindrical slide 62 after cutting a blank from the blank stock 70.

Since the distance between cutter 67 and the first forming work stage as well as the distance between the respective III'SI, second, third forming and piercing work stages. sometimes referred to as the pitch. are

equal as shown in FIGS. 2, 3C and 4, a unique, simple drive link 73 of the present invention is provided to connect slide block 64 with the parallel actuator plate 74 of the transfer clamp means 75 and effect the operation of transfer clamp means 75. Thus the transfer clamp means 75 will be operated as the hollow cylindrical slide 62 performs the above-mentioned cutting movement. Therefore, it is not necessary to provide a separate driving mechanism from crank shaft 20 to actuate plate 74 of transfer clamp means 75. While hollow cylindrical slide 62 moves forward and cuts the blank stock 70, transfer clamp means 75 moves simultaneously to perform its operation of grasping and transferring the nut blank from one stage to the next. When the hollow cylindrical slide 62 moves backward in timed relation, the transfer clamp means 75 also moves backward and grasps the newly cut nut blank and the freed blanks of forming stages I, 2 and 3 for proper positioning in conventional manner for the next forward movement of ram 40. In sequence of operations, the pierce will be processed by means of piercing die 90 and punch 91, then release of the pierced blank to discharge from the outlet 92 with a finished shape.

Also, the eccentric wheel 53 carries a cam plate 55, rotating in synchronism with shaft 20. The rotational motion of crank shaft 20 actuates the blank stock feeding mechanism 71 through cam plate 55 and the lever arms 56, 58 and connecting rod 57, so as to rock feeding roller 72 and conventionally step feed strip blank stock 70 through feeding tube 86 to be cut by cutter 67 carried by slide 62 and moved to the first forming stage.

Each forming stage is provided with a punch 83, 84 and and a cooperating die 80, 81 and 82 to shape the stock blank step-by-step into the final nut shape, for example a hexagonal nut blank. Since wear on the dies themselves is a problem, the present invention departs from conventional practice and provides respective dies in the form of replaceable bushings mounted in the right end wall of frame 10 as shown in FIGS. 2 and 5. Referring for the moment to FIG. 5 illustrating the final die for forming a hexagonal nut, each die 82 is formed with a main body portion externally threaded to cooperate with threaded passages formed in the end wall of frame 10 and a die hole 820 the configuration of which is conventional for the successive forming stages. A locknut 82b is preferably provided to resist turning movement of the die due to operational forces. In the case of abnormal wear, it is merely necessary to loosen locknut 82b and remove the worn die bushing.

A cam plate 59 is also mounted on end 25 of crank shaft 20 adjacent V-pulley 52 as shown in FIGS. 2 and 3B. A connecting rod 76 is operated by means of the rotation of crank shaft 20 through engagement of cam plate 59 with a rocker arm connected to one end of rod 76 and arm 77 connected to the opposite end of rod 76, and plate 78, which is mounted on the supporting arbor 79 journalled on a bracket formed on frame 10 (FIGS. 1, 2 and 3B). Actuation of rocker plate 78 actuates the respective pushout punches for dies 80, 81, 82 synchro nously with the timing of working. so that the pierced scrap will be discharged from outlet 93 (FIG. 3B).

The present invention, as stated hereinbefore, relates to a nut former, wherein the ram is operated by double crank arm connections; spherical roller bearings are provided on the rotating portions of the crank shaft to mount the crank arms; the driving source of the transfer clamp is transmitted by the hollow cylindrical slide of the blank cutter, so as to eliminate a separate driving means from the crank shaft; and the cutoff base is formed integrally with the frame.

The present invention, based on the inventors long experience in the field of nut manufacturing. provides improvements which:

1. Increase production efficiency by 40 percent;

2. Eliminate certain machine parts;

3. Simplify the mechanism;

4. Lower the manufacturing cost; and

5. Reduce the maintenance costs by more than 40 percent.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. In a nut former including a body frame, a power source and crankshaft drive connected to said power source, stock feed means, blank cutting means, a ram conventionally fitted with a plurality of forming punches and respective opposed forming dies conventionally coaxially related to said punches and cooperating with said punches to form respective laterally spaced blank forming stages equidistantly laterally spaced from one another and blank transfer clamp means for transferring cut blanks from said blank cutting means successively through said forming stages: ram drive means for reciprocating said ram and maintaining said ram laterally oriented in its reciprocating movement to assure delivery of an even impact force to said blanks to said respective forming stages comprising a longitudinally elongated crankshaft eccentric generally centered between the crankshaft ends; respective laterally aligned, body frame supported spherical bearings journalling said crankshaft outwardly of the opposite ends of said eccentric; respective spherical bearings mounted on the opposite ends of said eccentric; a pair of crank arms journalled on said last mentioned spherical bearings with the free arm ends of said crank arms connected to the laterally related opposite ends of said ram; and uniplanarly pivotable connection means connecting said free arm ends to said ram ends for assuring non-canted reciprocation of said ram.

2. The nut former ram drive means as claimed in claim 1 further comprising means for driving said blank transfer clamp means comprising means for guidingly mounting said blank cutting means for reciprocation in a plane normal to a plane defined by the common axes of said punches and forming dies and drive means for connecting said blank cutting means to said crankshaft to synchronize the reciprocation of said blank cutting means and said ram, a single drive link directly pivot ally interconnecting said means for guidingly mounting said blank cutting means and said blank transfer means whereby said blank transfer means and said blank cutting means reciprocate unidirectionally over an equal distance, means to limit the reciprocation stroke of said blank cutting means to a distance equal to the spacing between the respective forming stages, and means positioning the stock feed means to deliver the feed stock into the path of the blank cutter means at a point to assure severing of a blank during the limited reciprocation stroke of said blank cutting means.

3. The combination of claim 2 wherein said drive means for synchronizing reciprocation of said blank cutting means and said ram comprises an eccentric wheel mounted on an end of said crankshaft protruding beyond one side of said body frame in predetermined angular relation to said crankshaft eccentric, a link bar pin connected at one end to said eccentric wheel and at its other end to a slide plate guided for reciprocating movement in parallelism to said ram, said slide plate having an upwardly opening cam groove extending generally in the direction of reciprocation of said slide plate with its opposite ends laterally offset a distance equal to the spacing between said respective forming stages; said blank cutting means is disposed in spaced relation above said slide plate and includes a roller assembly including a follower roller depending into said cam groove, a slide block mounting a pivot pin connecting said drive link to said blank cutting means; and said means for guiding by mounting said blank cutting means comprises respective replaceable guide plates cooperating with said guide block.

4. The combination of claim 2 wherein said body frame along one side in juxtaposition to said blank transfer clamp means includes a cut off base formed as an integral part of said body frame; said blank cutting means comprises a hollow cylindrical slide supported in spanning relation by said one body frame side and the opposed side wall of said cut off base by sleeve bearings with one end protruding through said one body frame side and fixedly mounting a cutter blade for cutting nut blanks from the stock fed to the nut former; said drive means connecting said blank cutting means to said crankshaft includes a slide plate drive connected to said crankshaft, formed with an upwardly opening cam groove for limiting reciprocation of said hollow cylindrical slide, and guided for movement paralleling the path of reciprocation of said ram along slide surfaces formed in said cut off base; said hollow cylindrical slide includes a roller assembly, including a follower roller depending into said cam groove, a slide block mounting a pivot pin connecting said drive link to said blank cutting means; and said means for guidingly mounting said blank cutting means comprises respective replaceable guide plates cooperating with said guide block. 

1. In a nut former including a body frame, a power source and crankshaft drive connected to said power source, stock feed means, blank cutting means, a ram conventionally fitting with a plurality of forming punches and respective opposed forming dies conventionally coaxially related to said punches and cooperating with said punches to form respective laterally spaced blank forming stages equidistantly laterally spaced from one another and blank transfer clamp means for transferring cut blanks from said blank cutting means successively through said forming stages: ram drive means for reciprocating said ram and maintaining said ram laterally oriented in its reciprocating movement to assure delivery of an even impact force to said blanks to said respective forming stages comprising a longitudinally elongated crankshaft eccentric generally centered between the crankshaft ends; respective laterally aligned, body frame supported spherical bearings journalling said crankshaft outwardly of the opposite ends of said eccentric; respective spherical bearings mounted on the opposite ends of said eccentric; a pair of crank arms journalled on said last mentioned spherical bearings with the free arm ends of said crank arms connected to the laterally related opposite ends of said ram; and uniplanarly pivotable connection means connecting said free arm ends to said ram ends for assuring non-canted reciprocation of said ram.
 2. The nut former ram drive means as claimed in claim 1 further comprising means for driving said blank transfer clamp means comprising means for guidingly mounting said blank cutting means for reciprocation in a plane normal to a plane defined by the common axes of said punches and forming dies and drive means for connecting said blank cutting means to said crankshaft to synchronize the reciprocation of said blank cutting means and said ram, a single drive link directly pivotally interconnecting said means for guidingly mounting said blank cutting means and said blank transfer means whereby said blank transfer means and said blank cutting means reciprocate unidirectionally over an equal distance, means to limit the reciprocation stroke of said blank cutting means to a distance equal to the spacing between the respective forming stages, and means positioning the stock feed means to deliver the feed stock into the path of the blank cutter means at a point to assure severing of a blank during the limited reciprocation stroke of said blank cutting means.
 3. The combination of claim 2 wherein said drive means for synchronizing reciprocation of said blank cutting means and said ram comprises an eccentric wheel mounted on an end of said crankshaft protruding beyond one side of said body frame in predetermined angular relation to said crankshaft eccentric, a link bar pin connected at one end to said eccentric wheel and at its other end to a slide plate guided for reciprocating movement in parallelism to said ram, said slide plate having an upwardly opening cam groove extending generally in the direction of reciprocation of said slide plate with its opposite ends laterally offset a distance equal to the spacing between said respective forming stages; said blank cutting means is disposed in spaced relation above said slide plate and includes a roller assembly including a follower roller depending into said cam groove, a slide block Mounting a pivot pin connecting said drive link to said blank cutting means; and said means for guiding by mounting said blank cutting means comprises respective replaceable guide plates cooperating with said guide block.
 4. The combination of claim 2 wherein said body frame along one side in juxtaposition to said blank transfer clamp means includes a cut off base formed as an integral part of said body frame; said blank cutting means comprises a hollow cylindrical slide supported in spanning relation by said one body frame side and the opposed side wall of said cut off base by sleeve bearings with one end protruding through said one body frame side and fixedly mounting a cutter blade for cutting nut blanks from the stock fed to the nut former; said drive means connecting said blank cutting means to said crankshaft includes a slide plate drive connected to said crankshaft, formed with an upwardly opening cam groove for limiting reciprocation of said hollow cylindrical slide, and guided for movement paralleling the path of reciprocation of said ram along slide surfaces formed in said cut off base; said hollow cylindrical slide includes a roller assembly, including a follower roller depending into said cam groove, a slide block mounting a pivot pin connecting said drive link to said blank cutting means; and said means for guidingly mounting said blank cutting means comprises respective replaceable guide plates cooperating with said guide block. 